Twisted pair untwisting and stripping tool

ABSTRACT

A tool has a pair of untwisting projections and a spring biased slide with an insulation stripping blade. The projections have rounded edges forming a slot for untwisting a twisted pair of wires when the wires are pulled therethrough. The bias of the slide positions the stripping blade adjacent to the untwisting projections with the untwisting projections aligned with the stripping blade in position to receive the ends of the twisted pair of wires. During first movement of the wires relative to the tool, the ends of the wires are untwisted while the stripping blade and slide moves with the wires. When the slide engages a stop, continued movement of the wires strips the insulation from the ends of the wires.

United States Patent 1191 Raum et al.

111 3,736,606 51 June 5, 1973 [54] TWISTED PAIR UNTWISTING AND STRIPPINGTOOL [73} Assignee: Western Electric Company, Incorporated, New York,NY.

1221 Filed: June 1,1971

21 Appl.No.:148,682

[52] U.S. Cl. ..7/l4.1 R, 81/95 R [51] Int. Cl. ..H02g 1/12 [58] Fieldof Search ..7/l4.1 R; 140/123;

OTHER PUBLICATIONS Curley, Insulation Stripper For Twisted Wires, IBMTechnical Disclosure Bulletin, Vol. 3, No. 5 10-1960.

Primary Examiner-Granville Y. Custer, Jr.

Assistant ExaminerRoscoe V. Parker Att0rneyW. M. Kain, J. B. Hoofnagleand W. L. Williamson [57] ABSTRACT A tool has a pair of untwistingprojections and a spring biased slide with an insulation strippingblade. The projections have rounded edges forming a slot for untwistinga twisted pair of wires when the wires are pulled therethrough. The biasof the slide positions the stripping blade adjacent to the untwistingprojections with the untwisting projections aligned with the strippingblade in position to receive the ends of the twisted pair of wires.During first movement of the wires relative to the tool, the ends of thewires are untwisted while the stripping blade and slide moves with thewires. When the slide engages a stop, con; tinued movement of the wiresstrips the insulation from the ends of the wires.

A 4 Claims, 4 Drawing Figures PAIEWEUJUH 5 mm 3,736,606

JNVEN TURE J. 1-. num H. TILLJDHN EHJTTURNEH 1 TWISTED PAIR UNTWISTINGAND STRIPPING TOOL BACKGROUND OF THE INVENTION 1. Field of the InventionIn electronic equipment twisted pairs of wires are often used to connectselected terminals of the equipment. In making electrical connections,such as wrapped wire connections, it is necessary that the ends of thetwisted pairs of wires be untwisted and the insulation strippedtherefrom.

2. Description of the Prior Art In the prior art the untwisting andstripping of the ends of a tightly twisted pair of wires requires twooperations. In a first operation, an. operator pulls the ends of thetwisted pair of wires between the closed ends of an ordinary springclothes pin to untwist the ends. In the second operation, the operatoruses a conventional insulation stripping tool to strip the insulationfrom the untwisted ends of the pair of wires.

SUMMARY OF THE INVENTION Anobject of the invention is a new and improvedtool for untwisting and stripping the ends of a pair of twisted wires. I

Another object of the invention is a tool which allows an operator tountwist and strip the insulation from the ends of a pair of twistedwires in a single operation.

In accordance with these and other objects, atool embodying theprinciples of the invention includes a body with facilities for firstuntwisting the ends of a pair of twisted wires and then for strippingthe insulation from the ends of the pair of wires. The untwisting may beaccomplished by a pair of projections with rounded edges for untwistingthe wires as they are pulled between the edges. The stripping may beperformed by an insulation stripping blade mounted ona slide membermovable along with the wires relative to the body from a first positionto a second position whereupon the insulation is stripped.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of anembodiment of the invention. i

F IGS. 2 and 3 show two positions of a sliding member of the tool showninFlG. 1.

FIG. 4 illustrates the stripping of insulation from the ends of a pairof wiresby stripping blades of the apparatus shown in FIGS. l--3.

DETAILED DESCRIPTION Referring first to FIG. 1, there is shown a toolfor untwisting and stripping the ends of a pair of twisted wires. Thetool has a body or handle portion which is suitably shaped and/orknurled to be grasped and handled by an operator. The tool has a pair ofprojections 11 and 12 mounted on one end of the'body 10. The members 11and 12 have respective rounded edges 13 and 14 which face each other andare spaced apart to form a slot such that the ends of a pair of twistedwires are untwisted when pulled therebetween. The

projections 11 and 12 may be adjustably mounted on the body 10 such thatthe width of the slot between edges 13 and 14 may be adjusted toaccomodate different diameter wires. The width of the slot must begreater than approximately the diameter of either of the pair of wiresand must be less than the sum of the diameters of both of the pair ofwires. The projections 11 and 12 could also be biased together bysprings or air pressure so that the opening therebetween would beapproximately the diameter of one of the pair of wires.

An insulation stripping blade 15 is suitably mounted on an end of ashaft 17. The stripping blade 15 is forked with facing knife edges 18and 19 separated by a distance substantially less than the width of theouter diameter of the insulation, but slightly greater than the width ofthe metal conductor. The insulation stripping blade 15 severs sufficientinsulation that movement of the blade relative to ends of the wiresreadily pulls the insulation off the ends.

The shaft 17 slidably extends through a bore 21 into a cavity 22 of thebody 10. A spring 23 interposed between a head 24 of the shaft 17 and awall of the cavity 22 normally biases the shaft 17 to place the blade 15against the projections 11 and 12. The spring 23 has sufficientcompressive force to readily move the shaft 17. and blade 15 to a closedposition (FIG. 2) but insufficient to pull the insulation off of theends of the twisted pair of wires. A pin 20 mounted in the side of theshaft 17 extends into a slot 19-0f the body 10 for maintaining theinsulation severing blade in alignment with the projections 11 and 12.Additionally the pin 20 limits the forward movement of the shaft 17 andinsulation severing blade 15.

A wire cutter 26 is mounted on the body 10 in a conventional manner,i.e. screws etc. The wire cutter 26 has a pair of scissor-like blades 27and 28 which are closed by a thumb lever 29 to sever the ends of thepair of wires to a predetermined length. Conveniently, the cutter 26 maybe adjusted relative to the end of the body 10 to provide for changingthe length of wire which is stripped on the ends of the pair of wires.

Referring to FIG. 2, in operation a pair of twisted wires are placed byan operator between the edges 18 and 19 of the blade 15 and in the slotbetween the projections 11 and 12. The operator then operates the cutter26 to sever the ends of the pair of wires to-a predetennined length.Next the operator pulls the pair of wires away from the body 10, asshown in FIG. 3. The pair of wires are untwisted as they are pulledthrough the slot formed between the projections 1 1 and 12. The blade 15andthe shaft'17 move with the pair ofwires until the pin 20 engages theleft extremity of the slot 19, as shown in FIG. 3. Thereafter continuedmovementof the pair of wires away from the body 10 strips the insulationfrom the ends of the pair of wires as shown in FIG. 4.

The above-described embodiments of the invention are simply illustrativeof the principles of the invention and many embodiments may be devisedwithout departing from the scope and spirit of the invention. Forexample, the described tool is adapted to be held by an operator, butthe principles of the invention could readily be incorporated in a toolwherein the body is mounted on a bench or stand.

What is claimed is:

1. A tool for untwisting and stripping the insulation I such that thepair of twisted wires are untwisted when pulled through the slot;

a member slidably mounted relative to the body for moving in first andsecond opposite directions relative to said body;

stop means for limiting movement of the sliding member in the firstdirection;

an insulation stripping blade mounted on the sliding member in alignmentwith the projections; and

means for biasing the sliding member in the second direction to urge theinsulation stripping blade adjacent the projections in position toreceive the pair of twisted wires with the ends extending in the seconddirection, the biasing means allowing the insulation stripping blade andsliding member to move in the first direction when the pair of twistedwires are moved in the first direction to untwist the pair, to operatethe stop means and to strip the insulation from the ends of the pair.

2. A tool as defined in claim 1 which includes a wire cutter mounted onthe body for cutting the. ends of the pair of twisted wires to apredetermined length extending through the projections and insulationstripping blade.

3. A tool for untwisting and stripping theinsulation from the ends of apair of twisted wires comprising:

a body;

a pair of projections extending from the body, the

projections forming a slot therebetween with rounded edges, the slothaving a width greater than the diameter of either of the pair of wiresbut less than the sum of the diameters of both the wires such that thepair of twisted wires are untwisted when pulled through the slot;

a shaft slidably mounted in the body;

stop means on the body and shaft for preventing movement of the shaft ina first direction past a first position relative to the member; 7

an insulation stripping blade mounted on the shaft in alignment with theprojections for partially severing and gripping the insulation to bestripped; and

a spring for biasing the shaft in a second direction which is oppositethe first direction to urge the insulation stripping blade against theprojections in position to receive the pair of twisted wires with theends extending in the second direction, the spring allowing the shaft tomove in the first direction when the pair of twisted wires are'moved inthe first direction relative to the body to untwist the pair, to operatethe stop means and to strip the insulation from the end of the pair.

4. A tool as defined in claim 3, wherein the stop means includes:

a slot with a closed end; and a pin mounted on the shaft extending intothe slot with the closed end of the slot preventing movement of theshaft in the first direction pastthe first position.

1. A tool for untwisting and stripping the insulation from the ends of apair of twisted wires comprising: a body; a pair of projectionsextending from the body, the projections forming a slot therebetweenwith rounded edges, the slot having a width greater than the diameter ofeither of the pair of wires but less than the sum of the diameters ofboth the wires such that the pair of twisted wires are untwisted whenpulled through the slot; a member slidably mounted relative to the bodyfOr moving in first and second opposite directions relative to saidbody; stop means for limiting movement of the sliding member in thefirst direction; an insulation stripping blade mounted on the slidingmember in alignment with the projections; and means for biasing thesliding member in the second direction to urge the insulation strippingblade adjacent the projections in position to receive the pair oftwisted wires with the ends extending in the second direction, thebiasing means allowing the insulation stripping blade and sliding memberto move in the first direction when the pair of twisted wires are movedin the first direction to untwist the pair, to operate the stop meansand to strip the insulation from the ends of the pair.
 2. A tool asdefined in claim 1 which includes a wire cutter mounted on the body forcutting the ends of the pair of twisted wires to a predetermined lengthextending through the projections and insulation stripping blade.
 3. Atool for untwisting and stripping the insulation from the ends of a pairof twisted wires comprising: a body; a pair of projections extendingfrom the body, the projections forming a slot therebetween with roundededges, the slot having a width greater than the diameter of either ofthe pair of wires but less than the sum of the diameters of both thewires such that the pair of twisted wires are untwisted when pulledthrough the slot; a shaft slidably mounted in the body; stop means onthe body and shaft for preventing movement of the shaft in a firstdirection past a first position relative to the member; an insulationstripping blade mounted on the shaft in alignment with the projectionsfor partially severing and gripping the insulation to be stripped; and aspring for biasing the shaft in a second direction which is opposite thefirst direction to urge the insulation stripping blade against theprojections in position to receive the pair of twisted wires with theends extending in the second direction, the spring allowing the shaft tomove in the first direction when the pair of twisted wires are moved inthe first direction relative to the body to untwist the pair, to operatethe stop means and to strip the insulation from the end of the pair. 4.A tool as defined in claim 3, wherein the stop means includes: a slotwith a closed end; and a pin mounted on the shaft extending into theslot with the closed end of the slot preventing movement of the shaft inthe first direction past the first position.